(a) Field
The present invention relates to a switch controller and a converter including the same.
(b) Description of the Related Art
A soft switching converter uses a capacitor that is coupled in series or parallel to a main transformer for transforming power of a primary coil and transmitting it to a secondary coil. The soft switching converter controls switching operations of power switches according to resonance between the inductor of the main transformer and the capacitor. Then, zero voltage switching or zero current switching is performed to enable a soft switching operation.
In general, in the startup or burst mode operation of the converter, the switching operation of the power switches may fail in zero voltage switching, or a shoot-through current may occur by the switching operation of the power switches because a magnetizing current of the main transformer becomes unstable by a capacitor. The shoot-through current is generated at the main switch and an auxiliary switch when the main switch for supplying power to the primary coil of the converter and the auxiliary switch for transmitting the supplied power to the secondary coil are turned on.
Failure of zero voltage switching or the shoot-through current generates a steep rise of current and noise. The steep rise of current damages components of the converter such as a metal-oxide semiconductor field-effect transistor (MOSFET) that is a power switch.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.